With the advent of new telecommunication systems that require higher power, higher operational frequencies, and/or wider bandwidths, it is increasingly difficult to provide power amplifiers that exhibit desired efficiency and linearity characteristics. This may be particularly true for the amplifiers driving base stations in communications networks.
One specific type of power amplifier used in wireless communication systems is a Doherty power amplifier. Doherty power amplifiers are suitable for use in such applications because the amplifiers include separate amplification paths (e.g., a main path and a peaking path). The two paths are configured to operate in different modes. More particularly, the main amplification path typically operates in a class AB mode in which it provides gain at any power level, and the peaking amplification path typically operates in a class C mode in which it only conducts during half of the cycle. This can enable improved power-added efficiency of the amplifier, as compared to a balanced amplifier, at the power levels commonly encountered in wireless communications applications.